#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;
using maxt = atcoder::modint1000000007;

int main() {
  string S;
  cin >> S;
  if(S.at(0) == S.at(1) && S.at(1) != S.at(2)) {
    cout << "Yes" << endl;
  }
  else {
    cout << "No" << endl;
  }
}